Really its less that the document needs to be written "One" way and more that it will need to be as specific as possible. The less assumptions the program has to make the better the results will be. This means the fallowing:
A: Lets say you want a projectile to move when shot out. It will be necessary to specify this as the program will not be able to magically know what to do. There may be some rare exceptions for common genre conventions such as automatically handling coyote jumps for platformers unless told not to.
B: It will be necessary to use consistent wording so if you call a class a potion for example you will have to use potion for the entire document. The program will likely have some ability to recognize plurals but you should not call a potion a rock unless that is a variable or function in the potion class
Really the program will care less about the exact way the document is written and more so about keywords and their synonyms. Granted it will be necessary to look at the context for certain keywords so it will not completely ignore the sentence structure but its not like a programming language that always has to be worded in one way and nothing else will work.